I am programming a PLD using the WinCUPL software and I need some help.

I need to implement a state machine on the PLD and am using the SEQUENCE statement to define the
state transitions of the moore state diagram. However I have some unused states and I want to map them to don't cares (I know this is not advisable) using the 'DEFAULT' statement.

I am programming a PLD using the WinCUPL software and I need some help.

I need to implement a state machine on the PLD and am using the SEQUENCE statement to define the
state transitions of the moore state diagram. However I have some unused states and I want to map them to don't cares (I know this is not advisable) using the 'DEFAULT' statement.

Can anyone explain how to map to don't cares ?

Thanks

Click to expand...

In a career spanning half a century I never found a good reason for doing this and I don't think I'll start now.

Mapping unused states to don't cares. Every time I had a machine with unused states, those states would always trigger a machine RESET. Normally, this might happen at power-up. After that the defense against unused states is to make sure every transition goes to a valid state.

Now that you mention it the last time I programmed a PLD was over 20 years ago. That's virtually forever in silicon years.